Are you not scared about skipping warmups? This sounds like you aren't doing any. I was sick for a few days and decided to do some TRX rowing (20) and my elbow started to hurt the next day :)
Just do the first few at low intensity. A few push-ups or light kettlebell swings are a warmup for folks with a good strength baseline. For less fit folks, push-ups off the knees or body-weight squats would work the same way.